The present invention is directed to an immersion infrared thermometer for molten materials, such as steel, aluminum, salts and the like, and more specifically to a hollow tube having a closed end with infrared radiation detection means focused on the interior surface of the closed end and means for preheating the tube to prevent thermal shock on immersion of the tube into a molten material.
The present practice for determining the temperature of molten materials involves the use of electrical thermocouples which are adapted to be immersed in the molten material. However such electrical thermocouples will melt upon immersion in the molten material thereby wasting a thermocouple every time a temperature measurement is taken. Furthermore, due to the melting of the electrical thermocouple upon insertion into the molten material it is practically impossible to determine the exact depth at which the temperature is being measured.